JP4827347B2 - Manufacturing method of organic EL element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing technique of an organic EL element, and particularly relates to formation of an insulating layer using vapor deposition polymerization.
[0002]
[Prior art]
FIG. 5 is a cross-sectional view showing a configuration of a conventional organic EL element.
Conventionally, when manufacturing such an organic EL element 101, first, ITO electrodes 112 are formed in a stripe shape on a glass substrate 111.
[0003]
Next, an insulating layer 113 is formed in a pattern direction of the ITO electrode 112 and the cathode electrode 118 by using a photolithography method having a patterning process of a photoresist or a photosensitive polyimide.
[0004]
Further, after forming a reverse-tapered cathode partition wall (not shown), the hole transport layer 116 and the electron transport layer 117 are formed by vacuum deposition or spin coating, and then the cathode electrode 118 is formed by co-evaporation. .
[0005]
[Problems to be solved by the invention]
However, the insulating layer manufactured by such a conventional method has the following problems.
[0006]
(1) In wet methods such as spin coating and dipping, it is difficult to form a thin film having a thickness of 0.5 μm or less, for example, and many gases are released from the insulating layer.
[0007]
(2) In the insulating layer manufactured by the photoresist type, there is slight conductivity due to the influence of impurity ions and residual organic solvent due to the wet process, and the current flowing through the insulating layer is next to the point where the voltage is applied. There is also a problem that so-called crosstalk is generated at this point.
[0008]
(3) The curing temperature of photosensitive polyimide is as high as 400 ° C., which may deteriorate the quality of the ITO film.
[0009]
The present invention has been made in order to solve the problems of the conventional technique, and has an object to provide a technique for forming a thin film insulating layer having a good film quality and suitable for an organic EL element. To do.
[0010]
[Means for Solving the Problems]
The invention of claim 1, wherein has been made in order to achieve the above object, there is provided a method of manufacturing an organic EL device having a patterned insulating layer between an anode and a cathode on a substrate, as starting monomer, are diamine monomer and 4,4'-diaminodiphenyl ether (DDE), the steps of pyromellitic dianhydride with (PMDA), to form the insulating layer made of polyimide by heating in the vapor deposition polymerization and vacuum the acid component monomer, wherein And a step of forming an inorganic insulating film made of SiO ₂ on the insulating layer .
According to a second aspect of the invention, in the first aspect of the invention, the insulating layer has a thickness of 200 to 500 nm, and the inorganic insulating layer has a thickness of 50 to 70 nm .
[0011]
According to the present invention having such a configuration, since the insulating layer is formed by vapor deposition polymerization, for example, a thin film having a thickness of 0.5 μm or less can be easily formed.
Further, according to the present invention, the problem of crosstalk can be avoided because it is not formed by a wet process.
Furthermore, since the curing temperature can be lowered in the case of vapor deposition polymerization, the film quality of the anode made of the ITO film is not deteriorated.
Furthermore, in the present invention, an insulating layer excellent in insulation resistance can be obtained by forming an inorganic insulating film on the polymer film, and this inorganic insulating film is used as a mask by a dry process such as plasma etching. Patterning can be performed.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a schematic configuration of an example of a film forming apparatus for forming a partition wall of an organic EL element of the present invention.
[0013]
As shown in FIG. 1, this film forming apparatus 1 is a multi-chamber type single-wafer type apparatus, and is used for loading and unloading a substrate 10 around a core chamber 2 in which a transfer robot (not shown) is incorporated. The charging / unloading chamber 3, the vapor deposition polymerization chamber 4 for performing vapor deposition polymerization, the heat treatment chamber 5 for performing heat treatment, the ICP dry etching chamber 6 for performing etching, and the sputtering chamber 7 for performing sputtering are all arranged. They are connected via a gate valve (not shown).
[0014]
Further, the core chamber 2, the charging / discharging chamber 3, the vapor deposition polymerization chamber 4, the heat treatment chamber 5, the ICP dry etching chamber 6, and the sputtering chamber 7 are connected to a vacuum exhaust system having a vacuum pump (not shown). Further, the substrate 10 can be freely transported between the loading / unloading chamber 3, the vapor deposition polymerization chamber 4, the heat treatment chamber 5, the ICP dry etching chamber 6, and the sputtering chamber 7 by a robot disposed in the core chamber 2. It has become.
[0015]
FIG. 2 shows a schematic configuration of the vapor deposition polymerization chamber 4 of the film forming apparatus 1 shown in FIG.
As shown in FIG. 2, above the vapor deposition polymerization chamber 4, evaporation sources 40A and 40B of two kinds of raw material monomers A and B are connected via introduction pipes 41A and 41B.
[0016]
Evaporation containers 43A and 43B are provided in the housings 42A and 42B of the evaporation sources 40A and 40B, respectively. A diamine monomer and an acid component (anhydride) monomer are injected into the evaporation containers 43A and 43B as raw material monomers A and B for forming an aromatic polyimide film, respectively.
[0017]
In the present invention, examples of the diamine monomer include 4,4′-diaminodiphenyl ether (DDE), O-tolidine (OTD), 2,2′-bis [4- (4-aminophenoxy) phenyl] propane (BAPP ), 4,4'-diaminodiphenylmethane (MDA) and the like.
[0018]
Among these, DDE and MDA are particularly preferable from the viewpoint of good evaporation characteristics and reactivity.
[0019]
On the other hand, examples of the acid component monomer include pyromellitic dianhydride (PMDA), 3,3′-4,4′biphenyltetracarboxylic dianhydride (BPDA), 2,2′-bis (3,4 -Dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and the like.
[0020]
Among these, PMDA is particularly preferable because it has good evaporation characteristics and reactivity.
[0021]
Heaters 44A and 44B for heating the raw material monomers A and B are provided in the vicinity of the respective evaporation containers 43A and 43B.
[0022]
On the other hand, a heater 49 is wound around each of the introduction pipes 41A and 41B so that the temperature of the raw material monomers A and B can be controlled. In addition, valves 45A and 45B for adjusting the supply amounts of the raw material monomers A and B are provided in the middle of the introduction pipes 41A and 41B. Can be controlled.
[0023]
As shown in FIG. 2, a heating hot plate 46 is provided in the lower part of the vapor deposition polymerization chamber 4, and the substrate 10 is supported on the hot plate 46. And the mixing tank 47 formed so that it may spread toward the downward direction is provided in the upper part of the vapor deposition polymerization chamber 4. FIG. A heater 48 for heating the vapors of the raw material monomers A and B is provided on the inner wall of the mixing tank 47.
[0024]
3 (a) to 3 (d) and FIGS. 4 (e) to (h) are process diagrams showing an example of a method for producing an organic EL element according to the present invention.
[0025]
First, as shown in FIG. 3A, in the present invention, a predetermined substrate 10 having a patterned ITO electrode 12 as an anode formed on a glass substrate 11 is prepared.
[0026]
And this board | substrate 10 is carried in into the vapor deposition polymerization chamber 4 from the preparation taking-out chamber 3 of the film-forming apparatus 1 of FIG. 1, and the polyimide film 13 is formed on the board | substrate 10 by the vapor deposition polymerization method demonstrated below.
[0027]
In this case, first, the pressure in the vapor deposition polymerization chamber 4 is set to a high vacuum of about 3 × 10 ⁻³ Pa with the valves 45A and 45B being closed, and the raw material monomers A and B are predetermined by the heaters 44A and 44B. Heat to the temperature of.
[0028]
Then, after each raw material monomer A, B reaches a predetermined temperature and a required evaporation amount is obtained, each valve 45A, 45B is opened, and each raw material monomer A, B is placed on the substrate 10 from above at a predetermined evaporation rate. The polyamic acid film 13a, which is a polyimide precursor, is formed on the entire surface (see FIG. 3B), and then the valves 45A and 45B are closed.
[0029]
In this case, the evaporation rates of the raw materials monomers A and B are controlled so as to be 1: 1 in the stoichiometric ratio. Further, the temperature of the substrate 10 is controlled to a predetermined temperature by the hot plate 46.
[0030]
Thereafter, the substrate 10 is carried into the heat treatment chamber 5, and a predetermined heat treatment is performed on the polyamic acid film 13 a on the substrate 10 using the hot plate 46 .
[0031]
In this case, the heating condition is such that the temperature is raised to about 300 ° C. at a temperature rising rate of 5 ° C./min, and the state is maintained for about 15 minutes. The heat treatment is performed in a vacuum, for example.
[0032]
And as shown in FIG.3 (c), the polyimide film 13 is formed on the board | substrate 10 by this heat processing.
[0033]
In the case of the present invention, the thickness of the polyimide film 13 that is an insulating layer is not particularly limited, but is preferably 100 to 2000 nm, more preferably 200 from the viewpoints of insulation and film forming properties. ~ 500 nm.
[0034]
Thereafter, the substrate 10 is transferred to the sputtering chamber 7 , and an inorganic insulating film 14 is formed on the entire surface of the polyimide film 13 by sputtering as shown in FIG.
[0035]
In the present invention, the material of the inorganic insulating film 14 is not particularly limited, but from the viewpoint of insulation and workability, it is preferable to use SiO ₂ , SiN, etc., and more preferable materials are SiO _2. It is.
[0036]
The thickness of the inorganic insulating film 14 is not particularly limited, but is preferably 50 to 100 nm, more preferably 50 to 70 nm from the viewpoint of performing appropriate etching.
[0037]
Furthermore, although the inorganic insulating film 14 can be formed by sputtering or vapor deposition, it is preferably formed by sputtering from the viewpoint of improving the deposition rate and dealing with a large substrate.
[0038]
Then, a resist pattern 15 is formed on the inorganic insulating film 14 by a photoresist process, as shown in FIG.
[0039]
In this case, the resist pattern 15 is formed in a dot matrix. That is, it is formed so as to have a portion extending in parallel along the pattern of the ITO electrode 12 in the upper part between the adjacent ITO electrodes 12 and a portion extending perpendicularly thereto and parallel to a partition wall to be described later.
[0040]
Further, the substrate 10 is set in the ICP dry etching chamber 6, and the inorganic insulating film 14 on the ITO electrode 12 is removed by plasma etching using, for example, CF gas.
[0041]
Subsequently, using a 0 ₂ gas in the ICP dry etching chamber 6, to remove the polyimide film 13 on the ITO electrode 12 by plasma etching (see FIG. 4 (f)).
[0042]
The resist pattern 15 by etching using the 0 ₂ gas is also removed to some extent. The remaining resist pattern 15 is removed using a stripping solution such as acetone or a dedicated remover.
[0043]
As a result, as shown in FIG. 4G, the substrate 20 having the insulating layers 13 and 14 formed along the ITO electrode 12 as the anode electrode is obtained.
[0044]
Then, after forming a partition wall (not shown) by a photoresist process, a hole transport layer 16 made of, for example, NPD and an electron transport layer 17 made of, for example, Alq3 are formed by, for example, a vacuum evaporation method or a spin coat method (see FIG. 4 (h)).
[0045]
Further, the substrate 20 is carried into a vacuum vapor deposition chamber (not shown ), and the cathode 18 is formed by co-evaporation (for example, Mg: Ag = 10: 1) using, for example, Mg and Ag as vapor deposition materials. .
[0046]
Thereby, as shown in FIG. 4H, a passive matrix organic EL element 30 is obtained.
[0047]
As described above, according to the present embodiment, since the insulating layer 13 is formed by vapor deposition polymerization, for example, the insulating layer 13 having a thickness of 0.5 μm or less can be easily formed.
[0048]
Further, according to the present embodiment, since it is not formed by a wet process, the problem of crosstalk can be avoided.
[0049]
Furthermore, according to the present embodiment, in the case of vapor deposition polymerization, the curing temperature can be lowered to about 300 ° C., so that the film quality of the ITO electrode 12 as the anode is not deteriorated.
[0050]
Furthermore, in the present embodiment, an insulating layer excellent in insulation resistance can be obtained by forming the inorganic insulating film 14 on the polyimide film 13, and for example, plasma etching or the like can be obtained using this inorganic insulating film as a mask. Patterning can be performed by a dry process.
[0051]
The present invention can be applied not only when polyimide is used as the polymer material for the insulating layer, but also when polyurea or polyamide is used, but is most effective when polyimide is used. It is.
[0052]
【Example】
First, a substrate 10 (see FIG. 3A) in which an ITO electrode 12 was patterned on the glass substrate 11 described above was prepared.
[0053]
Next, a polyimide film 13 was formed on the entire surface of the substrate 10 in the vapor deposition polymerization chamber 4 using the film forming apparatus 1 shown in FIG.
[0054]
In this case, DDE and PMDA are used as the diamine monomer and the acid component monomer, and the vapors of the raw material monomers A and B evaporated in the evaporation sources 40A and 40B are introduced into the vapor deposition polymerization chamber 4 and held by the hot plate 46. A polyamic acid film as a polyimide precursor was formed to a thickness of 500 nm on the substrate 10 (see FIG. 3B).
[0055]
After the film formation was completed, the substrate 10 was transferred to the heat treatment chamber 5 and subjected to overheat treatment at a temperature of 300 ° C. for 15 minutes to complete the imidization reaction (see FIG. 3C).
[0056]
Thereafter, the substrate 10 was transferred to the sputtering chamber 7 , and an SiO ₂ film 14 that was inorganic insulation was formed on the polyimide film 13 over the entire surface by 50 nm by sputtering (see FIG. 3D).
[0057]
Then, a resist pattern 15 was formed on the SiO ₂ film 14 by a photoresist process (see FIG. 4E).
[0058]
The substrate 10 was set in the ICP dry etching chamber 6, and the SiO ₂ film 14 on the ITO electrode 12 was removed by plasma etching using a CF-based gas.
[0059]
Subsequently, using a 0 ₂ gas in ICP dry etching chamber 6 to remove the polyimide film 13 on the ITO electrode 12 by plasma etching (see FIG. 4 (f)).
[0060]
Further, the remaining resist pattern 15 was removed using acetone as a stripping solution.
[0061]
Thereby, the substrate 20 in which the insulating layers (13, 14) are formed along the ITO electrode 12 as the anode electrode is obtained (see FIG. 4G).
[0062]
Then, after a partition wall (not shown) is formed by a photoresist process, a hole transport layer 16 made of, for example, NPD and an electron transport layer 17 made of, for example, Alq3 are formed by, for example, a vacuum deposition method or a spin coating method (see FIG. 4 (h)).
[0063]
Further, the substrate 20 is carried into a vacuum vapor deposition chamber, and, for example, Mg and Ag are used as vapor deposition materials, and the cathode 18 is formed by a co-evaporation method (Mg: Ag = 10: 1) to form a passive matrix organic EL element. 30 was obtained (see FIG. 4 (h)).
[0064]
The emission characteristics of the organic EL element 30 obtained in this manner, the DC bias is applied to the predetermined dot, as a result of evaluating on whether dots other than the selected dot emits light, seen trouble crosstalk I couldn't.
[0065]
Further, a vapor deposition polymerization polyimide film having a thickness of 500 nm according to the present invention and an aluminum film having a thickness of 200 nm by a vacuum deposition method were formed on the ITO electrode 12, and the VI characteristics were examined.
[0066]
As a result, even when the electrode area is 4 mm ² and the applied voltage is 100 V, the current value is 1.5 × 10 ⁻¹² A and the SiO ₂ film is not present, it is confirmed that the film has excellent insulation resistance. It was.
[0067]
【The invention's effect】
As described above, according to the present invention, an excellent organic EL element having an insulating layer with high film quality can be manufactured.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an example of a film forming apparatus for forming a partition wall of an organic EL element of the present invention. FIG. 2 is a schematic configuration diagram of a vapor deposition polymerization chamber of the film forming apparatus shown in FIG. a)-(d): Process drawing which shows an example of the manufacturing method of the organic EL element which concerns on this invention (the 1)
FIGS. 4E to 4H are process diagrams showing an example of a method for producing an organic EL element according to the present invention (part 2).
FIG. 5 is a cross-sectional view showing the configuration of a conventional organic EL element.
1 ... film-forming apparatus 10 ... substrate 11 ... glass substrate 12 ... ITO electrode (anode) 13 ... Polyimide film (insulating layer) 14 ... SiO ₂ film (inorganic insulating film) 16 ... hole transport layer 17 ... electron transport layer 18 ... Cathode 30 ... Organic EL element

Claims (2)

A method for producing an organic EL device having a patterned insulating layer between an anode and a cathode on a substrate,
As the raw material monomer, 4,4'-diaminodiphenyl ether (DDE ), which is a diamine monomer, and pyromellitic dianhydride (PMDA), which is an acid component monomer, are used for the above insulation made of polyimide by vapor deposition polymerization and heating in vacuum. Forming a layer;
And a step of forming an inorganic insulating film made of SiO ₂ on the insulating layer . The thickness of the insulating layer is 200 to 500 nm, a method of manufacturing an organic EL element according to claim 1, wherein the thickness of the inorganic insulating layer is characterized in that it is a 50 to 70 nm.

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